This invention relates to digital thermostats which control operation of heating and/or cooling apparatus, and particularly to an improved means for establishing a desired set point temperature in such thermostats.
For many years, thermostats for controlling heating and/or cooling apparatus have incorporated a bi-metal sensitive to room temperature, a switching means carried by the bi-metal, which switching means controls operation of the heating and/or cooling apparatus, and a lever or knob mechanically linked to the bi-metal. Associated with the lever or knob is some type of temperature indexing means. The arrangement is such that the user can establish a desired set point temperature at which the thermostat is to effect energizing or de-energizing of the heating and/or cooling apparatus by simply manually adjusting the lever or knob so as to visually indicate the desired set point temperature.
In recent years, a wide variety of thermostats have been developed which have the capability of being programmed by the user to provide a time-temperature schedule whereby the thermostat will automatically control room temperature at different set point temperatures during different time periods of the day and week. Many of such programmable thermostats incorporate a microcontroller which provides digital logic. The microcontroller provides a cost-effective means for implementing the desired functions of such thermostats. The microcontroller, primarily because of its digital logic, also enables such thermostats to provide more accurate and reliable control of room temperature than can generally be achieved by the aforementioned bi-metal type.
While such programmable digital thermostats have been widely accepted in the marketplace, there still remains a segment of homeowners who, while desirous of the accuracy and reliability in controlling room temperature due to the use of a microcontroller in such thermostats, prefer a thermostat in which the set point temperature can be adjusted manually, and in a simple manner, for example, similar to that used in the aforementioned bi-metal types, instead of it being adjusted automatically in accordance with a programmed time-temperature schedule. While the key pads, slide switches, buttons, knobs and other such means utilized for programming the typical programmable digital thermostat may be manipulated quite simply to negate the automatic time-temperature operation and provide for manual adjustment of the set point temperature, such homeowners are often intimidated by the extent of such manipulation and/or by the overall complexity of such thermostats.
Therefore, it would be desirable to provide a non-programmable thermostat utilizing a microcontroller so as to implement the accuracy and reliability provided by the microcontroller, and utilizing a simple, easy-to-understand means for establishing a desired set point temperature.